• Please review our updated Terms and Rules here

Started work on the 11/780

S

stargeezer

Experienced Member
Joined
Apr 1, 2011
Messages
118
Location
Western NY
A few pictures from my latest acquisition. I started stripping out everything in the lower end to clean/repair.

SAM_2646.jpg
SAM_2642.jpg
SAM_2652.jpg
 
Congratulations and good luck with your 11/780!!!

I've got two of the little siblings of the 780: a VAX-11/750 and a VAX-11/725.

What do you intend to run on your 780 once it's functional again? VMS, ULTRIX, Unix ...

I want to run old versions of VMS (and ULTRIX) on my VAXen once they're up again.

If you intend to do the same let me know - I've got an extensive collection of old (pre V5) VMS software.

You will probably run into some of the similar problems I've got - The 780 and 750 VAXen share the same type of power supply, the H71xx PSU series.

Is your 780 "complete" (whatever that means)? Have you got some spares? Do you have all the manuals you need?

Please report about any progress/regress you experience - I'm very curious!

I wish you lots of fun and success!

Regards,

Ulli
 
vaxorcist said:
Congratulations and good luck with your 11/780!!!

I've got two of the little siblings of the 780: a VAX-11/750 and a VAX-11/725.

What do you intend to run on your 780 once it's functional again? VMS, ULTRIX, Unix ...

I want to run old versions of VMS (and ULTRIX) on my VAXen once they're up again.

If you intend to do the same let me know - I've got an extensive collection of old (pre V5) VMS software.

You will probably run into some of the similar problems I've got - The 780 and 750 VAXen share the same type of power supply, the H71xx PSU series.

Is your 780 "complete" (whatever that means)? Have you got some spares? Do you have all the manuals you need?

Please report about any progress/regress you experience - I'm very curious!

I wish you lots of fun and success!

Regards,

Ulli
Click to expand...

Hi Ulli,

Thanks! I used to have both of those machines and a 730 as well. I would LOVE to find another 725 again. In fact I still have the spare RC25 for it but unfortunately no cartridges. I did a lot of work with those TU58's getting them to work properly. I ran VMS on the 725 and Ultrix on the 750. I want to stick with an early version of VMS on this one. I'm doing some checking but I think this is an early example.

This is complete and only missing a MASSBUS cable. I am currently working on a trade for some spares but I am looking for whatever I can find for it. I'll PM you on some specifics.

Brian.
 
mc68010 said:
It looks really cold outside those windows. At least the garage will be nice and warm now.
Click to expand...


Its just in the garage to strip and clean. I have a nice place to work on the parts and when I get them fully stripped, they will be moved to their new building to be put back together.
 
Cool, you will have one of the biggest toys in the playpen. What’s it going to take to power something that size and I hope its not three phase, unless you have three phase service. Didn’t that system have some sort of disk pack drives? Glad to see people restoring and keeping the old systems of that size alive and always good to see someone who’s into this way more then me so I don’t have to feel bad about the couple rack systems I have.
 
Qbus said:
Cool, you will have one of the biggest toys in the playpen. What’s it going to take to power something that size and I hope its not three phase, unless you have three phase service. Didn’t that system have some sort of disk pack drives? Glad to see people restoring and keeping the old systems of that size alive and always good to see someone who’s into this way more then me so I don’t have to feel bad about the couple rack systems I have.
Click to expand...

Well the power controller is 3 Phase but it just uses it for load balancing. There is nothing in the 11/780 that needs 3 phase. In fact, you could run a minimal config of this guy from one 30A 120V outlet. Even so you can get a 3 phase motor conversion for $300 these days.

Yes, these usually used MASSBUS drives early one which some are 3 phase and very hard to find. This one has a UDA50 in it and I have a lot of DSI drives (RA81,90,etc)
 
Well the first problem I had was the H780 power supply in the LSI-11. Run light stayed on and no DC power light. I checked the voltages and the 5v was low and I had no 12v. I pulled it apart and did not see any obvious problems, I first suspected the caps and/or the switching transistors. A couple of people on classiccmp said they doubted the transistors were bad. After many years of building guitar amps, I knew caps would be the first thing to replace. My caps came in tonight and I soldered them in and voila! DC light and a prompt on the display. Success.

Here is the new caps installed.
SAM_2674.jpg

The old ones removed.
SAM_2677.jpg
 
Last edited:
You must log in or register to reply here.
Back
Top